package demo9;

/**
 * 完全背包-零钱兑换
 */
public class test3 {
    public int coinChange(int[] coins, int amount) {
        // 创建dp表
        int n = coins.length;
        int INF = 0x3f3f3f3f;
        int[][] dp = new int[n + 1][amount + 1];
        // 初始化
        for(int j = 1; j <= amount; j++){
            dp[0][j] = INF;
        }
        for(int i = 1; i <= n; i++){
            for(int j = 0; j <= amount; j++){
                dp[i][j] = dp[i - 1][j];
                if(j - coins[i - 1] >= 0){
                    dp[i][j] = Math.min(dp[i][j], dp[i][j - coins[i-1]] + 1);
                }
            }
        }
        return dp[n][amount] >= INF ? -1 : dp[n][amount];
    }

    // 优化
    public int coinChange2(int[] coins, int amount) {
        // 创建dp表
        int n = coins.length;
        int INF = 0x3f3f3f3f;
        int[] dp = new int[amount + 1];
        // 初始化
        for(int j = 1; j <= amount; j++){
            dp[j] = INF;
        }
        for(int i = 1; i <= n; i++){
            for(int j = coins[i-1]; j <= amount; j++){
                dp[j] = Math.min(dp[j], dp[j - coins[i-1]] + 1);
            }
        }
        return dp[amount] >= INF ? -1 : dp[amount];
    }
}
